Hi
I'm not sure but I've never seen this kind of search in all last releases I've used and I don't know if SAP are working or will work on this issue.
Now it can try to enhance the free selection of logical database KDF in order to add the criteria for bank: this is possible without to change the standard because LFBK is available in KDF.
The problem is IBAN is not in LFBK, but in TIBAN table so probably it should be changed KDF in order to insert TIBAN table.
Another solution could be enhance the search help for vendor KRED in order to add a new criteria for IBAN
Max